1. Field of the Invention
The present invention relates to an airbag start-up decision apparatus for a motorcycle, and particularly to an airbag start-up decision apparatus for a motorcycle wherein a start-up decision of an airbag is carried out using two acceleration sensors.
2. Description of Related Art
Conventionally, an airbag start-up decision apparatus decides whether or not an airbag disposed in front of an occupant is to be started up (inflated) in response to an output value of an acceleration sensor attached to a vehicle body. In such a start-up decision apparatus, a safing decision as a failsafe function for preventing an erroneous decision is sometimes applied.
In Japanese Patent Laid-Open No. 2003-237529, a start-up decision apparatus for an airbag of a four-wheel vehicle which has the following configuration is disclosed. In particular, two acceleration sensors (safing sensors) for carrying out a safing decision are provided on the left and right at front portions of a vehicle body are provided in addition to one acceleration sensor (G sensor) for carrying out a start-up decision (main decision) of an airbag. Even if the G sensor outputs a high output, if one or both of the safing sensors do not output a high output, then it is decided that the output of the G sensor arises from an influence of electric noise, and the airbag is not started up.
However, according to the technique disclosed in Japanese Patent Laid-Open No. 2003-237529, since three total acceleration sensors are required, a motorcycle, which has a limited installation space, has a subject in assurance of an installation space and a complicated wiring scheme. Further, increase of the number of sensors gives rise to increase of the number of parts and increase of the labor. Therefore, for an airbag for a motorcycle, a technique is demanded that achieves both a main decision and a safing decision using a minimized number of sensors.